Rajendra K. Pachauri (R), Chairman of the Intergovernmental Panel on Climate Change (IPCC), and Susan Solomon, Co-chair of IPCC Working Group 1, attend a news conference at UNESCO to present their report on the human link to pollution, global warming and climate change in Paris February 2, 2007. REUTERS/ Charles Platiau (FRANCE)

Photo: CHARLES PLATIAU

Rajendra K. Pachauri (R), Chairman of the Intergovernmental Panel...

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The village of Gusdorf, west of Cologne, is pictured in front of the lignite-fired power plant Frimmersdorf of German RWE AG energy company in this December 3, 2006 file photo. The Intergovernmental Panel on Climate Change (IPCC) February 2, 2007, released its long-awaited report assessing the human link to pollution, global warming and climate change. REUTERS/Arnd Wiegmann/Files (GERMANY)

Photo: ARND WIEGMANN

The village of Gusdorf, west of Cologne, is pictured in front of...

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A combination of two pictures shows a man as he removes snow from the roof of his house in the Bavarian village of Zwiesel near Deggendorf February 11, 2006 and the same location pictured on January 12, 2007. The Intergovernmental Panel on Climate Change (IPCC) February 2, 2007, released its long-awaited report assessing the human link to pollution, global warming and climate change. REUTERS/Michaela Rehle (GERMANY)

Photo: MICHAELA REHLE

A combination of two pictures shows a man as he removes snow from...

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A combination of two pictures shows a man as he removes snow from the roof of his house in the little Bavarian village of Mietraching near Deggendorf (top) February 10, 2006, and the same place on January 12, 2007. The Intergovernmental Panel on Climate Change (IPCC) February 2, 2007, released its long-awaited report assessing the human link to pollution, global warming and climate change. REUTERS/Michaela Rehle (GERMANY)

Photo: MICHAELA REHLE

A combination of two pictures shows a man as he removes snow from...

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A combination of two pictures shows a general view of the snow-covered houses of the Bavarian village of Zwiesel near Deggendorf (top) February 11, 2006, and the same location on January 12, 2007. The Intergovernmental Panel on Climate Change (IPCC) February 2, 2007, released its long-awaited report assessing the human link to pollution, global warming and climate change. REUTERS/Michaela Rehle (GERMANY)

Photo: MICHAELA REHLE

A combination of two pictures shows a general view of the...

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A combination photo shows vineyards in the south western German village of Durbach (upper) covered in snow in December 30, 2005, and (lower) without snow in January 2007. The Intergovernmental Panel on Climate Change (IPCC) February 2, 2007, released its long-awaited report assessing the human link to pollution, global warming and climate change. REUTERS/Vincent Kessler (GERMANY)

2007-02-02 09:39:00 PST SAN FRANCISCO -- An international body of climate scientists issued somber findings today that even more strongly confirm that Earth's rising air and ocean temperatures are very likely due to the increase in emissions from the burning of fossil fuels.

Even if the industrial nations start to immediately reduce emissions of carbon dioxide, methane and other greenhouse gases, the past and future gases will continue to contribute to global warming and the rise of oceans for more than 1,000 years, according to a long-awaited report released in Paris.

"Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level," said the report, a summary of four volumes of study representing the most-up-to-date knowledge on climate change.

The scientists credit improved worldwide computer modeling that confirm measurements on the ground, satellite data and ice core borings dating back 650,000 years with helping to build a picture of what has been happening to the planet. Some of the findings:

-- Arctic temperatures increased at almost twice the global rate in the past 100 years. The extent of the sea ice has shrunk nearly 3 percent per decade since 1978. Temperatures in the top layer of permafrost have increased since the 1980s, and the maximum area covered by seasonally frozen ground has decreased by about 7 percent in the Northern Hemisphere since 1900 with a decrease in spring of up to 15 percent.

-- Precipitation has significantly increased in eastern parts of North and South America, northern Europe and northern and central Asia. Drying has been seen in the Sahel, the Mediterranean, southern Africa and parts of southern Asia. Other regions are showing a high variability in rain and snowfall.

-- Mid-latitude westerly winds have strengthened in both hemispheres since the 1960s, and more intense and longer droughts have been observed over wide areas, particularly in the tropics and subtropics, since the 1970s.

-- Widespread changes in extreme temperatures have been observed over the last 50 years as cold days, cold nights and frost have become less frequent, while hot days, hot nights and heat waves have become more frequent.

Richard Somerville, a climate scientist at Scripps Institution of Oceanography and a coordinating lead author of a section of the report, said it seemed likely that these events would "carry on through the 21st century and continue to grow and become more serious as time goes by."

The release of the international assessment, heralded by shutting off lights in the Eiffel Tower for five minutes as the scientists rushed to finish, comes after six years of work and is built on a previous dozen years of study by hundreds of researchers from more than 100 nations. In the next two month, two more bodies of work dealing with different aspects of climate change will be released.

This part of the fourth assessment by the Intergovernmental Panel on Climate Change, or the IPCC, formed by the United Nations' Environment Program and World Meteorological Organization in 1988 to support a framework for study approved by the world's nations, including the United States.